As most have stated, this seems...well...impossible. Due to factors of temperature change and the normal diffusion of the air through the tube's rubber, it's hard to imagine a tire can hold it's pressure for a couple months - let alone 12 or so of them!

No offense, it's just hard to picture. I suppose if you have some "slimed" tubes, or equivalent, and ride them everyday keeping the "slime" coating the entire tube then it could happen, it just doesn't seem right.